Google is now offering customers of its Apps for Business communications and collaboration suite an optional service that automatically captures, archives and indexes their employees’ email messages and IM chat sessions.

Called Apps Vault, the new governance and e-discovery service is designed for companies that want to store that data and have it easily accessible—in case, for example, they're involved in a lawsuit or regulatory investigation and need to provide such information as part of the proceedings.

“With the ability to search and manage data based on terms, dates, senders, recipients and labels, Vault helps you find the information you need, when you need it,” Jack Halprin, Google’s Head of eDiscovery, wrote in a blog post on Wednesday.

Apps Vault, like the Apps suite, is cloud-based software. Google claims that customers can deploy Apps Vault “in a matter of minutes,” as opposed to traditional on-premise systems which can be difficult to set up. Apps Vault costs $5 per user, per month.

At that price, Apps Vault is more expensive than an existing similar service the company offers called Google Message Discovery, which is from the Postini product family and costs $33 per year, per user for Google Apps customers.

However, Halprin said in an interview that Apps Vault is worth the higher price, because it has been built from the ground up as part of Google Apps, and as such is significantly easier to set up and manage.

It also works more efficiently on the back-end. Unlike conventional systems of this sort, including the Postini product, Vault doesn’t make copies of the content it tracks and put it in separate repository. Instead, when an end user “deletes” emails and IM sessions, they are only removed from the user-interface view but not deleted from Google Apps servers.

Halprin also said that Vault’s price puts it within reach of small- and medium-sized businesses that traditionally haven’t been able to afford this type of system, whether cloud-based or on-premise.

For the time being, Google will continue offering both Vault and the Postini product.

Currently Apps Vault is only available to new Apps customers signing up for the service for the first time. Later, Apps Vault will be available to existing Apps customers, and Google will offer automated data migration for companies that use the Postini product and want to switch.

Google also plans to expand the breadth of Apps content that Vault can capture and archive beyond the current Gmail email messages and on-the-record Gmail IM chat sessions. For example, Vault at this point doesn’t monitor IM sessions conducted through the Google Talk IM client; in the future, it could.

Apps for Business, which includes Gmail, Talk, Calendar, Docs, Sites, IT management and security features, costs $50 per user, per year. A month-to-month option costs $5 per user, per month.